DNEPROPETROVSK, Ukraine — A fear of war has returned to Dnepropetrovsk, carried by the tensions surrounding Sunday’s referendum in Crimea on whether to declare independence from Ukraine and join Russia and by deadly clashes that erupted this weekend near the eastern border.

With Russian forces massing along the frontier, worries run especially deep among the city’s Jewish population of 40,000 — including Holocaust survivors — which has enjoyed a renaissance in recent decades in large part thanks to efforts by Boston’s Jewish community.

“People are afraid of the Russian tanks. If they get into [the border regions of] Donetsk and Lugansk, why not come here,” said Shmuel Kaminetzky, the chief rabbi.